1 /* Normalization forms (composition and decomposition) of Unicode strings.
2 Copyright (C) 2001-2002, 2009-2023 Free Software Foundation, Inc.
3 Written by Bruno Haible <bruno@clisp.org>, 2009.
4
5 This file is free software: you can redistribute it and/or modify
6 it under the terms of the GNU Lesser General Public License as
7 published by the Free Software Foundation; either version 2.1 of the
8 License, or (at your option) any later version.
9
10 This file is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 #ifndef _UNINORM_H
19 #define _UNINORM_H
20
21 /* Get size_t. */
22 #include <stddef.h>
23
24 #include "unitypes.h"
25
26 #if @HAVE_UNISTRING_WOE32DLL_H@
27 # include <unistring/woe32dll.h>
28 #else
29 # define LIBUNISTRING_DLL_VARIABLE
30 #endif
31
32
33 #ifdef __cplusplus
34 extern "C" {
35 #endif
36
37
38 /* Conventions:
39
40 All functions prefixed with u8_ operate on UTF-8 encoded strings.
41 Their unit is an uint8_t (1 byte).
42
43 All functions prefixed with u16_ operate on UTF-16 encoded strings.
44 Their unit is an uint16_t (a 2-byte word).
45
46 All functions prefixed with u32_ operate on UCS-4 encoded strings.
47 Their unit is an uint32_t (a 4-byte word).
48
49 All argument pairs (s, n) denote a Unicode string s[0..n-1] with exactly
50 n units.
51
52 Functions returning a string result take a (resultbuf, lengthp) argument
53 pair. If resultbuf is not NULL and the result fits into *lengthp units,
54 it is put in resultbuf, and resultbuf is returned. Otherwise, a freshly
55 allocated string is returned. In both cases, *lengthp is set to the
56 length (number of units) of the returned string. In case of error,
57 NULL is returned and errno is set. */
58
59
60 enum
61 {
62 UC_DECOMP_CANONICAL,/* Canonical decomposition. */
63 UC_DECOMP_FONT, /* <font> A font variant (e.g. a blackletter form). */
64 UC_DECOMP_NOBREAK, /* <noBreak> A no-break version of a space or hyphen. */
65 UC_DECOMP_INITIAL, /* <initial> An initial presentation form (Arabic). */
66 UC_DECOMP_MEDIAL, /* <medial> A medial presentation form (Arabic). */
67 UC_DECOMP_FINAL, /* <final> A final presentation form (Arabic). */
68 UC_DECOMP_ISOLATED,/* <isolated> An isolated presentation form (Arabic). */
69 UC_DECOMP_CIRCLE, /* <circle> An encircled form. */
70 UC_DECOMP_SUPER, /* <super> A superscript form. */
71 UC_DECOMP_SUB, /* <sub> A subscript form. */
72 UC_DECOMP_VERTICAL,/* <vertical> A vertical layout presentation form. */
73 UC_DECOMP_WIDE, /* <wide> A wide (or zenkaku) compatibility character. */
74 UC_DECOMP_NARROW, /* <narrow> A narrow (or hankaku) compatibility character. */
75 UC_DECOMP_SMALL, /* <small> A small variant form (CNS compatibility). */
76 UC_DECOMP_SQUARE, /* <square> A CJK squared font variant. */
77 UC_DECOMP_FRACTION,/* <fraction> A vulgar fraction form. */
78 UC_DECOMP_COMPAT /* <compat> Otherwise unspecified compatibility character. */
79 };
80
81 /* Maximum size of decomposition of a single Unicode character. */
82 #define UC_DECOMPOSITION_MAX_LENGTH 32
83
84 /* Return the character decomposition mapping of a Unicode character.
85 DECOMPOSITION must point to an array of at least UC_DECOMPOSITION_MAX_LENGTH
86 ucs_t elements.
87 When a decomposition exists, DECOMPOSITION[0..N-1] and *DECOMP_TAG are
88 filled and N is returned. Otherwise -1 is returned. */
89 extern int
90 uc_decomposition (ucs4_t uc, int *decomp_tag, ucs4_t *decomposition);
91
92 /* Return the canonical character decomposition mapping of a Unicode character.
93 DECOMPOSITION must point to an array of at least UC_DECOMPOSITION_MAX_LENGTH
94 ucs_t elements.
95 When a decomposition exists, DECOMPOSITION[0..N-1] is filled and N is
96 returned. Otherwise -1 is returned. */
97 extern int
98 uc_canonical_decomposition (ucs4_t uc, ucs4_t *decomposition);
99
100
101 /* Attempt to combine the Unicode characters uc1, uc2.
102 uc1 is known to have canonical combining class 0.
103 Return the combination of uc1 and uc2, if it exists.
104 Return 0 otherwise.
105 Not all decompositions can be recombined using this function. See the
106 Unicode file CompositionExclusions.txt for details. */
107 extern ucs4_t
108 uc_composition (ucs4_t uc1, ucs4_t uc2)
109 _UC_ATTRIBUTE_CONST;
110
111
112 /* An object of type uninorm_t denotes a Unicode normalization form. */
113 struct unicode_normalization_form;
114 typedef const struct unicode_normalization_form *uninorm_t;
115
116 /* UNINORM_NFD: Normalization form D: canonical decomposition. */
117 extern @GNULIB_UNINORM_NFD_DLL_VARIABLE@ const struct unicode_normalization_form uninorm_nfd;
118 #define UNINORM_NFD (&uninorm_nfd)
119
120 /* UNINORM_NFC: Normalization form C: canonical decomposition, then
121 canonical composition. */
122 extern @GNULIB_UNINORM_NFC_DLL_VARIABLE@ const struct unicode_normalization_form uninorm_nfc;
123 #define UNINORM_NFC (&uninorm_nfc)
124
125 /* UNINORM_NFKD: Normalization form KD: compatibility decomposition. */
126 extern @GNULIB_UNINORM_NFKD_DLL_VARIABLE@ const struct unicode_normalization_form uninorm_nfkd;
127 #define UNINORM_NFKD (&uninorm_nfkd)
128
129 /* UNINORM_NFKC: Normalization form KC: compatibility decomposition, then
130 canonical composition. */
131 extern @GNULIB_UNINORM_NFKC_DLL_VARIABLE@ const struct unicode_normalization_form uninorm_nfkc;
132 #define UNINORM_NFKC (&uninorm_nfkc)
133
134 /* Test whether a normalization form does compatibility decomposition. */
135 #define uninorm_is_compat_decomposing(nf) \
136 ((* (const unsigned int *) (nf) >> 0) & 1)
137
138 /* Test whether a normalization form includes canonical composition. */
139 #define uninorm_is_composing(nf) \
140 ((* (const unsigned int *) (nf) >> 1) & 1)
141
142 /* Return the decomposing variant of a normalization form.
143 This maps NFC,NFD -> NFD and NFKC,NFKD -> NFKD. */
144 extern uninorm_t
145 uninorm_decomposing_form (uninorm_t nf)
146 _UC_ATTRIBUTE_PURE;
147
148
149 /* Return the specified normalization form of a string. */
150 extern uint8_t *
151 u8_normalize (uninorm_t nf, const uint8_t *s, size_t n,
152 uint8_t *_UC_RESTRICT resultbuf, size_t *lengthp);
153 extern uint16_t *
154 u16_normalize (uninorm_t nf, const uint16_t *s, size_t n,
155 uint16_t *_UC_RESTRICT resultbuf, size_t *lengthp);
156 extern uint32_t *
157 u32_normalize (uninorm_t nf, const uint32_t *s, size_t n,
158 uint32_t *_UC_RESTRICT resultbuf, size_t *lengthp);
159
160
161 /* Compare S1 and S2, ignoring differences in normalization.
162 NF must be either UNINORM_NFD or UNINORM_NFKD.
163 If successful, set *RESULTP to -1 if S1 < S2, 0 if S1 = S2, 1 if S1 > S2, and
164 return 0. Upon failure, return -1 with errno set. */
165 extern int
166 u8_normcmp (const uint8_t *s1, size_t n1, const uint8_t *s2, size_t n2,
167 uninorm_t nf, int *resultp);
168 extern int
169 u16_normcmp (const uint16_t *s1, size_t n1, const uint16_t *s2, size_t n2,
170 uninorm_t nf, int *resultp);
171 extern int
172 u32_normcmp (const uint32_t *s1, size_t n1, const uint32_t *s2, size_t n2,
173 uninorm_t nf, int *resultp);
174
175
176 /* Converts the string S of length N to a NUL-terminated byte sequence, in such
177 a way that comparing uN_normxfrm (S1) and uN_normxfrm (S2) with uN_cmp2() is
178 equivalent to comparing S1 and S2 with uN_normcoll().
179 NF must be either UNINORM_NFC or UNINORM_NFKC. */
180 extern char *
181 u8_normxfrm (const uint8_t *s, size_t n, uninorm_t nf,
182 char *resultbuf, size_t *lengthp);
183 extern char *
184 u16_normxfrm (const uint16_t *s, size_t n, uninorm_t nf,
185 char *resultbuf, size_t *lengthp);
186 extern char *
187 u32_normxfrm (const uint32_t *s, size_t n, uninorm_t nf,
188 char *resultbuf, size_t *lengthp);
189
190
191 /* Compare S1 and S2, ignoring differences in normalization, using the
192 collation rules of the current locale.
193 NF must be either UNINORM_NFC or UNINORM_NFKC.
194 If successful, set *RESULTP to -1 if S1 < S2, 0 if S1 = S2, 1 if S1 > S2, and
195 return 0. Upon failure, return -1 with errno set. */
196 extern int
197 u8_normcoll (const uint8_t *s1, size_t n1, const uint8_t *s2, size_t n2,
198 uninorm_t nf, int *resultp);
199 extern int
200 u16_normcoll (const uint16_t *s1, size_t n1, const uint16_t *s2, size_t n2,
201 uninorm_t nf, int *resultp);
202 extern int
203 u32_normcoll (const uint32_t *s1, size_t n1, const uint32_t *s2, size_t n2,
204 uninorm_t nf, int *resultp);
205
206
207 /* Normalization of a stream of Unicode characters.
208
209 A "stream of Unicode characters" is essentially a function that accepts an
210 ucs4_t argument repeatedly, optionally combined with a function that
211 "flushes" the stream. */
212
213 /* Data type of a stream of Unicode characters that normalizes its input
214 according to a given normalization form and passes the normalized character
215 sequence to the encapsulated stream of Unicode characters. */
216 struct uninorm_filter;
217
218 /* Bring data buffered in the filter to its destination, the encapsulated
219 stream, then close and free the filter.
220 Return 0 if successful, or -1 with errno set upon failure. */
221 extern int
222 uninorm_filter_free (struct uninorm_filter *filter);
223
224 /* Create and return a normalization filter for Unicode characters.
225 The pair (stream_func, stream_data) is the encapsulated stream.
226 stream_func (stream_data, uc) receives the Unicode character uc
227 and returns 0 if successful, or -1 with errno set upon failure.
228 Return the new filter, or NULL with errno set upon failure. */
229 extern struct uninorm_filter *
230 uninorm_filter_create (uninorm_t nf,
231 int (*stream_func) (void *stream_data, ucs4_t uc),
232 void *stream_data)
233 _GL_ATTRIBUTE_DEALLOC (uninorm_filter_free, 1);
234
235 /* Stuff a Unicode character into a normalizing filter.
236 Return 0 if successful, or -1 with errno set upon failure. */
237 extern int
238 uninorm_filter_write (struct uninorm_filter *filter, ucs4_t uc);
239
240 /* Bring data buffered in the filter to its destination, the encapsulated
241 stream.
242 Return 0 if successful, or -1 with errno set upon failure.
243 Note! If after calling this function, additional characters are written
244 into the filter, the resulting character sequence in the encapsulated stream
245 will not necessarily be normalized. */
246 extern int
247 uninorm_filter_flush (struct uninorm_filter *filter);
248
249
250 #ifdef __cplusplus
251 }
252 #endif
253
254
255 #endif /* _UNINORM_H */